Cigar box guitarist & builder, Shane Speal (ShaneSpeal.com) demonstrates an easy technique for loosening the shafts on new volume pots, making them more playable. Using an older electric cigar box guitar that he recently overhauled, Speal shows exactly where to spray the shaft of the 500k pot with Radio Shack contact cleaner. See video and photo below.
A looser volume knob will enable easier roll-offs and volume swells in concert.
Extra : Here are links to the parts used in the videos